Dataset Information

Evidence for non-communicable diseases: analysis of Cochrane reviews and randomised trials by World Bank classification.

ABSTRACT:

Introduction

Prevalence of non-communicable diseases (NCDs) is increasing globally, with the greatest projected increases in low-income and middle-income countries. We sought to quantify the proportion of Cochrane evidence relating to NCDs derived from such countries.

Methods

We searched the Cochrane database of systematic reviews for reviews relating to NCDs highlighted in the WHO NCD action plan (cardiovascular, cancers, diabetes and chronic respiratory diseases). We excluded reviews at the protocol stage and those that were repeated or had been withdrawn. For each review, two independent researchers extracted data relating to the country of the corresponding author and the number of trials and participants from countries, using the World Bank classification of gross national income per capita.

Results

797 reviews were analysed, with a reported total number of 12 340 trials and 10 937 306 participants. Of the corresponding authors 90% were from high-income countries (41% from the UK). Of the 746 reviews in which at least one trial had met the inclusion criteria, only 55% provided a summary of the country of included trials. Analysis of the 633 reviews in which country of trials could be established revealed that almost 90% of trials and over 80% of participants were from high-income countries. 438 (5%) trials including 1 145 013 (11.7%) participants were undertaken in low-middle income countries. We found that only 13 (0.15%) trials with 982 (0.01%) participants were undertaken in low-income countries. Other than the five Cochrane NCD corresponding authors from South Africa, only one other corresponding author was from Africa (Gambia).

Discussion

The overwhelming body of evidence for NCDs pertains to high-income countries, with only a small number of review authors based in low-income settings. As a consequence, there is an urgent need for research infrastructure and funding for the undertaking of high-quality trials in this area.

SUBMITTER: Heneghan C

PROVIDER: S-EPMC3703573 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evidence for non-communicable diseases: analysis of Cochrane reviews and randomised trials by World Bank classification.

Heneghan C C Blacklock C C Perera R R Davis R R Banerjee A A Gill P P Liew S S Chamas L L Hernandez J J Mahtani K K Hayward G G Harrison S S Lasserson D D Mickan S S Sellers C C Carnes D D Homer K K Steed L L Ross J J Denny N N Goyder C C Thompson M M Ward A A

BMJ open 20130706 7

<h4>Introduction</h4>Prevalence of non-communicable diseases (NCDs) is increasing globally, with the greatest projected increases in low-income and middle-income countries. We sought to quantify the proportion of Cochrane evidence relating to NCDs derived from such countries.<h4>Methods</h4>We searched the Cochrane database of systematic reviews for reviews relating to NCDs highlighted in the WHO NCD action plan (cardiovascular, cancers, diabetes and chronic respiratory diseases). We excluded re ...[more]

PMID: 23833146

Similar Datasets

Project description:ObjectiveSystematic reviews can include cluster-randomised controlled trials (C-RCTs), which require different analysis compared with standard individual-randomised controlled trials. However, it is not known whether review authors follow the methodological and reporting guidance when including these trials. The aim of this study was to assess the methodological and reporting practice of Cochrane reviews that included C-RCTs against criteria developed from existing guidance.MethodsCriteria were developed, based on methodological literature and personal experience supervising review production and quality. Criteria were grouped into four themes: identifying, reporting, assessing risk of bias, and analysing C-RCTs. The Cochrane Database of Systematic Reviews was searched (2nd December 2013), and the 50 most recent reviews that included C-RCTs were retrieved. Each review was then assessed using the criteria.ResultsThe 50 reviews we identified were published by 26 Cochrane Review Groups between June 2013 and November 2013. For identifying C-RCTs, only 56% identified that C-RCTs were eligible for inclusion in the review in the eligibility criteria. For reporting C-RCTs, only eight (24%) of the 33 reviews reported the method of cluster adjustment for their included C-RCTs. For assessing risk of bias, only one review assessed all five C-RCT-specific risk-of-bias criteria. For analysing C-RCTs, of the 27 reviews that presented unadjusted data, only nine (33%) provided a warning that confidence intervals may be artificially narrow. Of the 34 reviews that reported data from unadjusted C-RCTs, only 13 (38%) excluded the unadjusted results from the meta-analyses.ConclusionsThe methodological and reporting practices in Cochrane reviews incorporating C-RCTs could be greatly improved, particularly with regard to analyses. Criteria developed as part of the current study could be used by review authors or editors to identify errors and improve the quality of published systematic reviews incorporating C-RCTs.

Project description:ObjectiveAcupuncture is commonly practiced in Korea and is regularly evaluated in clinical trials. Although many Cochrane reviews of acupuncture include searches of both English and Chinese databases, there is no information on the value of searching Korean databases. This study aimed to investigate the impact of searching Korean databases and journals for trials eligible for inclusion in existing Cochrane acupuncture reviews.MethodsWe searched 12 Korean databases and seven Korean journals to identify randomised trials meeting the inclusion criteria for acupuncture reviews in the Cochrane Database of Systematic Reviews. We compared risk of bias assessments of the Korean trials with the trials included in the Cochrane acupuncture reviews. Where possible, we added data from the Korean trials to the existing meta-analyses in the relevant Cochrane review and conducted sensitivity analyses to test the robustness of the results.ResultsSixteen Korean trials (742 participants) met the inclusion criteria for eight Cochrane acupuncture reviews (125 trials; 13,041 participants). Inclusion of the Korean trials provided data for 20% of existing meta-analyses (24 out of 120). Inclusion of the Korean trials did not change the direction of effect in any of the existing meta-analyses. The effect size and heterogeneity remained mostly unchanged. In only one meta-analysis did the significance change. Compared to the studies included in the Cochrane acupuncture reviews, the risk of bias in the Korean trials was higher in terms of outcome assessor blinding and allocation concealment.ConclusionsMany Korean studies contributed additional data to the existing meta-analyses in Cochrane acupuncture reviews. Although inclusion of these studies did not alter the results of the meta-analyses, comprehensive searches of the literature are important to avoid potential language bias. The identification and inclusion of eligible Korean trials should be considered for reviews of acupuncture.

Project description:IntroductionThe validity of systematic reviews and meta-analysis depends on methodological quality and unbiased dissemination of trials. Our objective is to evaluate the association of estimates of treatment effects with different bias-related study characteristics in meta-analyses of interventions used for treating pain in osteoarthritis (OA). From the findings, we hope to consolidate guidance on interpreting OA trials in systematic reviews based on empirical evidence from Cochrane reviews.Methods and analysisOnly systematic reviews that compare experimental interventions with sham, placebo or no intervention control will be considered eligible. Bias will be assessed with the risk of bias tool, used according to the Cochrane Collaboration's recommendations. Furthermore, center status, trial size and funding will be assessed. The primary outcome (pain) will be abstracted from the first appearing forest plot for overall pain in the Cochrane review. Treatment effect sizes will be expressed as standardised mean differences (SMDs), where the difference in mean values available from the forest plots is divided by the pooled SD. To empirically assess the risk of bias in treatment benefits, we will perform stratified analyses of the trials from the included meta-analyses and assess the interaction between trial characteristics and treatment effect. A relevant study-level covariate is defined as one that decreases the between-study variance (τ(2), estimated as Tau-squared) as a consequence of inclusion in the mixed effects statistical model.Ethics and disseminationMeta-analyses and randomised controlled trials provide the most reliable basis for treatment of patients with OA, but the actual impact of bias is unclear. This study will systematically examine the methodological quality in OA Cochrane reviews and explore the effect estimates behind possible bias. Since our study does not collect primary data, no formal ethical assessment and informed consent are required.Trial registration numberPROSPERO (CRD42013006924).

Project description:A focus on equity in health can be seen in many global development goals and reports, research and international declarations. With the development of a relevant framework and methods, the Campbell and Cochrane Equity Methods Group has encouraged the application of an 'equity lens' to systematic reviews, and many organizations publish reviews intended to address health equity. The purpose of the Evidence for Equity (E4E) project was to conduct a priority-setting exercise and apply an equity lens by developing a knowledge translation product comprising summaries of systematic reviews from the Cochrane Library. E4E translates evidence from systematic reviews into 'friendly front end' summaries for policy makers.The following topic areas with high burdens of disease globally, were selected for the pilot: diabetes/obesity, HIV/AIDS, malaria, nutrition, and mental health/depression. For each topic area, a "stakeholder panel" was assembled that included policymakers and researchers. A systematic search of Cochrane reviews was conducted for each area to identify equity-relevant interventions with a meaningful impact. Panel chairs developed a rating sheet which was used by all panels to rank the importance of these interventions by: 1) Ease of Implementation; 2) Health System Requirements; 3)Universality/Generalizability/Share of Burden; and 4) Impact on Inequities/Effect on equity. The ratings of panel members were averaged for each intervention and criterion, and interventions were ordered according to the average overall ratings.Stakeholder panels identified the top 10 interventions from their respective topic areas. The evidence on these interventions is being summarized with an equity focus and the results posted online, at http://methods.cochrane.org/equity/e4e-series .This method provides an explicit approach to setting priorities by systematic review groups and funders for providing decision makers with evidence for the most important equity-relevant interventions.

Dataset Information

Evidence for non-communicable diseases: analysis of Cochrane reviews and randomised trials by World Bank classification.

Introduction

Methods

Results

Discussion

Publications

Evidence for non-communicable diseases: analysis of Cochrane reviews and randomised trials by World Bank classification.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets